Alginate encapsulation of the white rot fungus Phanerochaete chrysosporium

Abstract

In the laboratory, the white rot fungus Phanerochaete chrysosporium degrades numerous organic pollutants. Lack of a slow-release delivery system to toxic waste sites, for this and other fungi, however, constitutes an important barrier to practical implementation. In this study, the use of calcium alginate as an encapsulant for mycelia was investigated; samples were in the form of pellets 1-3 mm in diameter. When refrigerated, alginate- embedded mycelia of P. chrysosporium were viable for one year, both with and without nutrient supplementation. At room temperature, in the absence of nutrient supplementation, viability decreased sharply within 2 months. Addition of sawdust or corncob grits extended the viability of alginate- embedded mycelia; nevertheless, after 9 months only about 20% of the pellets stored at room temperature yielded fungal growth. Spores of P. chrysosporium, embedded in alginate pellets together with corncob grits, gave 75% viability after 9 months of storage at room temperature. Alginate-embedded mycelia were used in Petri plate toxicity tests with 2,4,6-trinitrotoluene (TNT) and gave more rapid and reproducible results than tests performed with mycelial plugs. These experiments demonstrated the feasibility of encapsulating P. chrysosporium in calcium alginate pellets, thus providing a potential method of delivering white rot fungi to toxic waste sites, as well as for developing a system of standardized toxicity testing in plate assays.